The primary goal is to develop new treatments for childhood leukemias and lymphomas. The following projects are currently underway or in preparation: 1) Pilot Study of Non-Myeloablative, HLA-Matched Allogeneic Stem Cell Transplantation in Pediatric Leukemias and Lymphomas 2) Anti-CD22 Immunotoxins for Treatment of Leukemias and Lymphomas in Childhood 3) Unconjugated Monoclonal Antibodies for Treatment Lymphomas In Childhood 4) EPOCH-Rituximab for HIV-Associated Non-Hodgkin's Lymphomas In Childhood 5) Phase II Study of UCN-01 In Relapsed Or Refractory Systemic Anaplastic Large Cell And Mature T-Cell Lymphomas 6) WT1 Peptide-Transduced Allogeneic Dendritic Cell Vaccine for Hematologic Malignancies 7) Hematologic Malignancy Biology Study